Pap to the Pen: A Quick and Dirty Look

There’s been a lot of conjecture about whether the move of Papelbon to the pen will have a positive or negative effect on the Red Sox 2006 season. Some have suggested that the move has handed the division to the Yankees, while others have said it has sured up a former weak spot. I think it might provide some insight to look at David Gassko’s THT chaining article, which he used previously to discuss Papelbon’s move to the rotation.

I’ll handle this a little differently than David, though. DSG’s work used a generic bullpen (RA=run average, LI=leverage index, RAR=runs above replacement:

RA	LI	IP	RAR
3.00	1.70	80	30
3.40	1.20	80	17
3.80	1.00	80	11
4.20	0.80	80	6
4.60	0.70	80	2
5.00	0.60	80	0

But we have real actual players to put in place. To estimate how each will do in a relief vs. starting role, I’ve used their ZIPS projections for 07 and Dan Szymborski’s pitcher conversion tool. For the sake of this exercise, let’s also assume that before the big move, Pineiro was going to be the closer, Donnelly the top setup man, and Tavarez the next setup man:

RA	LI	IP	RAR
5.03	1.70	80	-.4 (Pineiro)
4.66	1.20	60	3.7 (Donnelly)
4.75	1.06	80	2.4 (Tavarez)

Instead, we’ll now have this at the top of the BP:

RA	LI	IP	RAR
3.44	1.70	70	 20.6 (Pap)
5.03	1.28	80	-.3 (Pineiro)
4.66	1.03	60	2.3 (Donnelly)

Note that I’ve adjusted the LI in each case to reflect the fact that some players are not pitching the full 80 innings allotted under DSG’s study. So, for example, because Donnelly only throws 60 IP in the first scenario, 20 of his 1.2 LI innings are given to Tavarez, boosting his LI to 1.06. (This adjustment isn’t perfect, but it made very little difference anway--only fractions of a run.)

So because of the Pap move, the Red Sox save some 16.9 runs (22.6 – 5.7) over their previous bullpen alignment. But what do they lose in the rotation? Here, we can pretty much throw leverage out the window and focus on raw RAR.

RA		IP	RAR
4.45		160	27.6 (Pap)
5.82		160	3.2 (Tavarez)

I’ve assumed that both guys will throw around 160 IP, which falls into WAG territory. My reasoning being that that’s pretty much the most either has thrown in a season and the Red Sox would be likely to coddle Pap for obvious reasons. Overall, it looks like having Tavarez in the rotation will cost the Sox 24.4 runs.

So what’s the overall impact of this move? It costs the Red Sox 24.4 runs in the rotation, while saving them 16.9 runs in the pen--a net loss of 7.5 runs.

Now, there are plenty of things that could skew this either way. You might think Tavarez is likely to do better as a starter than 5.82 RA, or maybe watching Papelbon last year makes you think the 3.44 RA I’ve given him is too high. It’s also unlikely that a replacement level closer will remain in that role.

But overall, this gives a very basic look at the impact of Papelbon’s move to the pen. It’s expected to cost the team three-quarters of a win. I think it’s easy to imagine that with such a small margin of difference (which could easily be wiped out by the assumptions I’ve made here), intangibles such as player comfort and health concerns could easily overwhelm the statistical differences.